1. Field of the Invention
The present invention relates to a high-speed shear for transverse cutting of a rolled strip to a length and including a first upper blade drum having a comparatively large diameter and carrying a first blade, a second lower blade drum having a comparatively small diameter and carrying a second blade, and a drive transmission for rotationally connecting the first and second blade drums, with the first and second blade cooperating with each other in a predetermined cutting position of the first and second blade drums for cutting the rolled strip.
2. Description of the Prior Art
Generally, high-speed shears for transverse cutting a rolled strip to a length are well known. Thus, German Publication DE 197 46 528A discloses a high-speed shear having two drums one of which carries a chisel cutter and the other of which carries an anvil that cooperates with the chisel cutter for cutting the strip. A controlled adjusting device displaces the two drums toward each other for cutting a run-through strip. The synchronization of the displacement of the two drums is effected by using electrical, electronic, and mechanical means.
European Publication EP 0 904 877A2 discloses a high-speed shear with blade drums the diameters and speeds of which differ only insignificantly, and which are driven by an external divider mechanism. The drums are brought into a cutting position, in which the blades are located opposite each other, by a lever-operated setting mechanism and, after cutting the strip, the drums are moved away from each other.
German Publication DE-OS 26 54 866 discloses a flying shear with blade drums rotationally connected with each other. The disclosed shear has a drum rotating device with a force transmitting mechanism that connects the two drums and insures that their speeds are synchronized with the running speed of the fed material. This German Publication further discloses a drum adjusting device for displacing the drums between an open position and a cutting position, and a control unit for controlling the motor of the adjusting device and which controls the displacement of the drums between the open and cutting position.
In the shear disclosed in DE-OS 26 54 866 the ratio of the diameters of the first and second drums in equal 2 to 3, and their rotation is so coordinated that the second drum performs two revolution per three revolution of the first drum. The drum setting or adjusting device is so controlled that the first and second drums are in the cutting position after six revolutions of the first drum and four revolution of the second drum.
As it follows from the disclosure of DE-OS 26 54 866, in particular FIG. 2, the force transmitting mechanism, which connects the drums, the drum adjusting device, and the control unit are very complicated and are failure-prone. The force transmitting mechanism has five tooth gears engaging each other so that the accumulated tooth backlash results in deviation of the angular positions of the blade drums for predetermined positions which can lead to the damage of the shear and also result in an unclean cut.
Accordingly, an object of the present invention is to provide a high-speed shear for cutting hot and/or cold strips which would insure obtaining of a precise cut with the strip being transported with a high speed.
Another object of the present invention is to provide a high-speed shear for cutting hot and/or cold strips which would insure obtaining of a precise cut of strips having minimal thicknesses and transported with high-speeds.
A further object of the present invention is to provide a high-speed shear having a simple structure and non-complicated mechanical and/or electronic mechanisms.
A still further object of the present invention is to provide a high-speed shear in which the danger of the blades or even entire shear being damaged is eliminated.
Yet another object of the present invention is to provide a high-speed shear having reduced mounting and maintenance costs.